Steam-boiler eubbtace



status T ECE STEAM-BOITIER FURNAC.

Specification of Letters Patent No. 31,743, ldated March 19, 1861.

To all whom it may concern:

Be it known that I, J. R. ROBINSON, of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Steam-Boiler Furnaces, (No. 3 and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a central longitudinal vertical section of a boiler with my improvement applied. Fig. 2 is a transverse vertical section of the same, in the line fr, m, marked in Fig. 1'. Fig. 3 is a horizontal section of the same.

Similar letters of reference indicate corresponding parts in the several figures.

This invention, ,which is applicable both to horizontal and upright boilers, consists in a certain construction and `arrangement of a gas-mixing chamber directly over the fire chamber, and between the latter and the flue or iiues or tubes of the boiler, and communicating with the fire-chamber by a certain arrangement of openings for the introduction and mixing of the gases, and the air which leaves the ire chamber in an uncombined state.

To enable others skilled in the art to make and use my invention I will proceed to describe its construction and operation.

The boiler Vrepresented in the drawing is of the horizontal multitubular kind with a lire-box. In adapting the invention to this kind of boiler the inner portion a Z) o (l, corresponding with the fire-box of an ordinary locomotive or other fire-box boiler, is made much deeper in a vertical direction than an ordinary Firebox, and a little longer from back to front; and a wall A, is erected across the rear of the said portion in rear of the grate B, and not far from the front tube-sheet CZ, such wall extending all across from side to side, and from top to bottom` of the said portion a c (l. The fire-chamber C, and the gas-mixing chamber D, are formed in front of this wall A, the gasmixing chamber being formed by throwing an arch E, of fire-brick across the space in front of the said wall, at a suitable distance above the grate, leaving suitable openings c, e, in the said arch close to the sides a, o, of the box a o c cl, for the escape of the gases from the iire chamber into the mixingchamber. In the wall A, an opening j, is left above the arch E, to constitute an outlet from the mixingchamber D, through which the gases pass to the space G, in rear of the wall before entering the tubes f, f. In the crown o f the arch E, there is an opening' to, fitted with a sliding valve or damper h, of fire-brick, which may be opened and closed by. a hook inserted through a door z', in front of the boiler.

The greater portion of the gases and un combined air from the fire-chamber passes into the mixing chamber D, by the side openings c, and in passing over the edges of these openings they are vcaused to have a rolling or eddy-like motion toward the center of the chamberl where they are perfectly mixed and combined before escaping' by the openings j, to the tubes f, 7. The lighter gases have a tendency to collect in the upper part of the fire chamber in the concave of the arch E, but their escape into the mixing chamber is provided for by the opening g, by which they are admitted to the latter chamber in such a manner as to mix freely with and aid in mixing the gases which have entered by the openings c, c. slide 7L, is opened more or less according to the character of the fuel and the proportion 'of the lighter gases evolved from it.

7c is a hole for cleaning out the bottom of the space G, and Z, is a door for closing said opening.

In applying this invention to an upright boiler, the inner portion corresponding with the fire-box of an ordinary boiler is made much deeper than when no mixing chamber is used, and an arch or dome is constructed across Vthe tire-box at a suitable distance above the grate, the space above this arch or dome and below the tubes or flues constituting the mixing chamber, and the said arch or dome havinga system of openings c, c, g, substantially as herein specified with reference to the horizontal boiler.

What I claim as my invention, and desire to secure by Letters Patent, is

l. The construction and arrangement of the gasmixing chamber D, directly over the The Y fire-chamber, With openings 6,6,at the sides chamber `amd fitted With 2L valve or damper thereof, substantially as herein described. in, substantially as and for the purpose herein 2. In combination with the so constructed specified. and arranged gas-mixing Chamber and its J. R. ROBINSON. 5 side openings e, e, the opening g, at the Vitnesees:

crown of the arch E, or its equivalent, com- EDWIN H. CHAMBERLIN, municating With Jche highest part of the iire- GEO. S. BOMHARDT. 

